The invention at hand relates to the field of ventilatory support devices, such as transnasal insufflation and tracheotomy systems, specifically to the connection between a tracheotomy patient and a high flow therapy device as is used for transnasal insufflation and is sufficiently known from the state of the art (WO 2008/060 295 A2, DE 10 2006 019 402 A1). In the following, these devices will be referred to as TNI devices (transnasal insufflation devices) for short.
The nasal high flow ventilatory support by means of TNI devices, also referred to as nasal high flow therapy (NHF), is finding more widespread use in intensive care, for it has proven to be a viable alternative to the known oxygen therapy and to positive-pressure ventilation which is used for patients suffering from respiratory insufficiency. Moreover, patients find the open system used in nasal high flow therapy more agreeable than the closed pressure systems with tightly strapped ventilation masks, making the former more widely accepted.
The therapy rests upon the nasal application of a warmed up and wetted air/oxygen mixture FiO2 having a flow rate of 2 to 60 l/min, which is administered into the nostrils (3) coming from a TNI device (5) via a connecting tube (4) and prongs (2) of a nasal cannula (1) (cf. FIG. 1). In this instance, the prongs (2) protrude into the nostrils (3) by approximately 3 mm, with enough space remaining around the prongs (2) so that the unrequired air/oxygen mixture FiO2 and the exhaled spent air can be discharged into the environment in the breathing pauses and during exhalation (open system). Owing to a flow rate set at the TNI device (5), which is typically larger than the patient's peak flow, a stable air/oxygen mixture FiO2 results in the nose, resulting in a consistent supply status for the patient.
When administering a sufficient flow rate, a PEEP (positive end-expiratory pressure) is generated, which has an impact all the way to the alveolar level via the trachea and supports ventilation. This positive physical effect in particular assists the therapy. Nasal secretions and moisture cannot impair the open system as these are also flushed out past the prongs (2) of the nasal cannula (1). The warm and moistened air/oxygen mixture FiO2 thus supports mucociliary cleansing.
In summary, nasal high flow therapy (NHF) is a new and already successfully employed form of therapy with which high oxygen concentrations can be offered, a drying out of the respiratory tracts is prevented, the proportion of the dead space ventilation is reduced and the nasal dead space is washed out. Furthermore, an end-expiratory positive respiratory pressure accumulates when performing the therapy, which counteracts a collapse of the respiratory tracts. Respiratory efficiency is increased and the required respiratory effort is reduced, which contributes to the relief of the respiratory muscle pump. All these advantageous features lead to the anticipation of NHF as the standard therapy used in the fields of respiratory insufficiency, such as chronic respiratory insufficiency, albeit a series of examinations are currently being conducted and first positive findings are available. NHF is a non-invasive ventilatory support which is mainly used for intermitting ventilation.
This differs from the known ventilation via a tracheostoma, in which the patients' breathing is supported via a tracheal cannula inserted into the trachea by piercing through the soft tissue in the neck. This invasive form of artificial ventilation, which is enabled by a surgical procedure, is mostly administered as a continuous long-term ventilation for securing the respiratory tract after accidents and operations or in weaning procedures, albeit this form of artificial ventilation can be interrupted for several hours at a time as long as the tracheotomy patient can endure it. Advantages of tracheotomy are, among other things, a lesser risk of damaging the vocal cords by bypassing the upper respiratory tract and a reduction of the respiratory dead space, which alleviates breathing for the patient.